Signal separation system used for an automated classification of white blood cells

Abstract

A signal separation system is used to discriminate cytoplasm of white blood cells from a sample of white blood. The signal separation system includes a light source generating light passed through a blood sample, a light separator for separating green and blue light beams from the light passed through the sample, first and second photoelectric converters for changing the green and the blue light beams to first and second electric signals, a signal treatment circuit which converts the first and the second electric signals to binary signals with respect to certain threshold levels and then forms a separation signal from the binary signals, and the gate circuit which separates the signal component of the white blood cells from the sample with the function of the separation signal.

We claim: 
     
       1. A signal separation system comprising: first means for generating a beam of light and directing said beam of light through a sample of whole blood;   second means, disposed in the path of the light beam which has passed through said sample of whole blood, for separating said light beam into first and second light beams, the magnitude of information representative of the nuclei of white blood cells in said sample being higher in said first light beam than in said second light beam, and the magnitude of information representative of red blood cells in said sample being higher in said second light beam than in said first light beam;   third means, disposed to receive said first and second light beams, for generating first and second electric signals representative thereof;   fourth means, receiving the first and second electric signals generated by said third means, for quantizing said first and second electric signals with respect to first and second prescribed threshold levels, and producing respective first and second binary signals representative of the quantized first and second electric signals;   fifth means, coupled to said fourth means, for combining said first and second binary signals and producing a first separation signal which contains a signal component representative of the nuclei of white blood cells in said sample and a signal component representative of red blood cells in said sample; and   sixth means, coupled to said fifth means, and said third means, and responsive to said first separation signal and the output of said third means, for producing a second separation signal representative of the cytoplasm in the white blood cells of said sample.   
     
     
       2. A signal separation system according to claim 1, wherein said first and second light beams have respectively different wavelengths. 
     
     
       3. A signal separation system according to claim 2, wherein the wavelength of said first light beam lies in the green region of the optical spectrum and the wavelength of said second light beam lies in the blue region of the optical spectrum. 
     
     
       4. A signal separation system according to claim 3, wherein said sixth means comprises a gate circuit, which is controlled by said first separation signal to gate said first electric signal therethrough, and   a binary quantizing circuit which receives the output of said gate circuit and produces said second separation signal.   
     
     
       5. A signal separation system according to claim 4, wherein said fourth means comprises first and second binary quantizers which receive said first and second electric signals, respectively, and produce said first and second binary signals, and wherein said fifth means comprises an adder circuit which adds said first and second binary signals, from said first and second binary quantizers, to each other, and an inverter circuit connected to the output of said adder circuit.   
     
     
       6. A signal separation system according to claim 3, wherein said sixth means comprises a gate circuit, which is controlled by said first separation signal,   a subtractor circuit, coupled to said third means, to subtract said first and second electric signals from each other,   a delay circuit coupled between said subtractor circuit and said gate circuit, and   a binary quantizing circuit which receives the output of said delay circuit, as gated by said gate circuit under the control of said first separation signal, and produces said second separation signal.   
     
     
       7. A signal separation system according to claim 4, wherein said sixth means further comprises a delay circuit coupled to said third means, for delaying said first electric signal therefrom and applying the delayed first electric signal to said gate circuit. 
     
     
       8. A signal separation system according to claim 4, wherein said fourth means comprises first and second analog-to-digital converters for converting said first and second electric signals into first and second digital signals, respectively, and   first and second binary converters for converting said first and second digital signals into said first and second binary signals, respectively.   
     
     
       9. A signal separation system according to claim 8, wherein said sixth means further comprises a delay circuit coupled to said third means, for delaying said first electric signal therefrom and applying the delayed first electric signal to said gate circuit. 
     
     
       10. A signal separation system according to claim 8, wherein said sixth means further includes a shift register connected between the output of said first analog-to-digital converter and said gate circuit, said first digital signal being applied to said shift register. 
     
     
       11. A signal separation system according to claim 8, wherein said sixth means further includes an inverter circuit connected to the output of said second analog to digital converter,   an adder, connected to the output of said inverter circuit and said first analog-to-digital converter, and   a shift register connected between the output of said adder and said gate circuit.   
     
     
       12. A signal separation system according to claim 1, wherein said first means comprises a flying spot scanner, and said third means comprises first and second respective photomultiplier tubes. 
     
     
       13. A signal separation system according to claim 1, wherein said third means comprises first and second respective scanning type image pick-up tubes. 
     
     
       14. A signal separation system according to claim 5, wherein each of said first and second binary quantizers comprises a maximum level detector and hold circuit and a minimum level detector and hold circuit, coupled to receive a respective one of said first and second electric signals, a subtraction circuit connected to subtract the outputs of said maximum level detector and hold circuit and said minimum level detector and hold circuit from each other, and a threshold comparator circuit for comparing the level of a respective one of said first and second electric signals with a prescribed threshold level as determined by the output of said subtraction circuit. 
     
     
       15. A signal separation system according to claim 8, wherein each of said first and second binary converters respectively comprises a first memory circuit coupled to receive a respective one of said first and second digital signals,   second and third memory circuits, the memory contents of which are initally presettable,   first and second comparing circuits, coupled to the outputs of said second and third memory circuits, for comparing the contents of said second and third memory circuits with the contents of said first memory circuit and for causing the contents of said second and third memory circuits to be respectively rewritten only in response to the contents of said second and third memory circuits being respectively higher and lower than that of said first memory circuit,   an operational circuit, connected to said second and third memory circuits, for detecting whether or not the difference between the contents of said second and third memory circuits exceeds a preselected threshold level, and   a comparator circuit, for comparing the respective one of said first and second electrical signals with the output of said operational circuit, and converting the respective one of said first and second binary signals in accordance with said comparison.